No one is surprised by Trump having extra marital affairs - he's been paying women for sex his entire life, and all his later marriages were the result of them. What IS important is that Trump knew that exposure of the newest ones (during his current marriage) would likely have affected the election, just like John Edwards. That is the criminal act and why it is so destructive. But, Republicans don't care about destruction - they do it all the time. Criminality is a constant in Republican politics.
